1. Field of the Invention
This invention relates generally to a packaging method and apparatus, and more specifically, to a packaging method and apparatus for continuously forming covers; particularly covers attached to flexible commodity-containing packages.
2. Description of the Prior Art
Flexible strip packages having commodity-containing compartments for pills, capsules, granular materials and like items, are well known in the prior art. These packages generally include thin flexible walls formed of sheet material, for example, Cellophane, metal foil and the like. Most preferably the sheet material is thermoplastic, and can be softened by heat. Alternatively, the sheet material can include a thermoplastic or adhesive coating to permit juxtaposed layers of said sheet material to be bonded together by the application of heat and pressure, or by the application of pressure alone, to form seals about respective commodity-containing compartments of the package. It is common practice to seal the above-described strip packages within more rigid covers, as disclosed in U.S. Pat. Nos. 2,457,924; 2,325,921; 2,069,332 and 2,069,334. All of the above patents are issued to Leroy L. Salfisberg, who pioneered much of the early work in this area. The covers for the flexible packages protect the packages against damage, provide rigidity for aiding in displaying the packages and provide a carrier for identifying indicia, such as the name of the product, the ingredients of the product, the dosage requirements, etc.
A preferred cover construction is disclosed in U.S. Pat. No. 2,457,924. That cover is generally in the form of a matchbook, and includes a back panel positioned on one side of the flexible package, a front panel overlying the opposite side of the package and a catch strip overlying a free marginal end of the front panel for retaining said front panel in a closed position. The flexible strip package is generally sealed to inwardly facing surfaces of the back panel and the catch strip. In the prior art methods of forming a matchbook-type cover, a single strip of material generally is folded to form the front and back panels, as well as the catch strip. The flexible commodity-containing package is then manually fed between the catch strip and the back panel of each cover, and is sealed by a manual operation; generally with the aid of a hand-crimping tool. This prior art method of forming covered strip packages is quite slow; thereby resulting in undesirably high production costs.
Another type of protective cover suggested in the prior art includes only front and back panels, or leaves, and its construction is similar to a book cover. Most commonly, this type of package is formed by folding a single web of material along a medial line. Sections of the web on opposite sides of the fold-line constitute the front and back panels of the cover. The medial line provides a junction between the panels, and the flexible package generally includes a sealing strip that is heat-sealed to both panels at the fold junction.
U.S. Pat. No. 2,245,827 disclosed an apparatus for continuously forming flexible commodity-containing packages, filling the packages as they are being formed, and thereafter sealing the packages within a cover of the type having front and back leaves. Each cover is formed from a separate sheet which is fed intermittently from a stack into an assembly zone. In the assembly zone, the package is bonded to the sheet, and the sheet is folded into a cover. This intermittent process of forming a protective cover about each flexible package is generally quite slow, and therefore undesirably enhances the production cost of forming covered packages.
Flexible commodity-containing packages for pills, capsules, granulated material and similar commodities have been formed from continuous webs of material in a continuous processing operation, as exemplified by the disclosures in U.S. Pat. Nos. 2,162,230, issued to Salfisberg; 2,468,517, issued to Salfisberg and 3,451,187, issued to Massey et al. In the continuous formation of these flexible commodity-containing packages, it has also been suggested to form opposed walls from two continuous webs cut from a single roll of sheet material, e.g. U.S. Pat. Nos. 2,162,230 and 3,451,187.
Although it has been suggested to form flexible commodity-containing packages in a continuous process, there has been no suggestion, to applicant's knowledge, of continuously forming protective covers for these packages, or continuously attaching the covers to the packages.